Structural properties of a family of hydrogen-bonded co-crystals formed between gemfibrozil and hydroxy derivatives of t-butylamine, determined directly from powder X-ray diffraction data

We report the formation and structural properties of co-crystals containing gemfibrozil and hydroxy derivatives of t-butylamine H₂NC(CH₃)_3−n(CH₂OH)_n, with n=0, 1, 2 and 3. In each case, a 1:1 co-crystal is formed, with transfer of a proton from the carboxylic acid group of gemfibrozil to the amino group of the t-butylamine derivative. All of the co-crystal materials prepared are polycrystalline powders, and do not contain single crystals of suitable size and/or quality for single crystal X-ray diffraction studies. Structure determination of these materials has been carried out directly from powder X-ray diffraction data, using the direct-space Genetic Algorithm technique for structure solution followed by Rietveld refinement. The structural chemistry of this series of co-crystal materials reveals well-defined structural trends within the first three members of the family (n=0, 1, 2), but significantly contrasting structural properties for the member with n=3.     

Worst allocations of policy limits and deductibles

In the literature, orderings of optimal allocations of policy limits and deductibles were established with respect to a policyholder’s preference. However, from the viewpoint of an insurer, the orderings are not enough for the purpose of pricing. In this paper, by applying the equivalent utility premium principle, we study worst allocations of policy limits and deductibles for an insurer, which give rise to the maximum fair premiums. Closed-form solutions are derived. Then we present a result concerning the optimality in a general risk-sharing scheme, by which we obtain optimal allocations for policyholders directly from worst allocations for an insurer. Several results in Cheung [Cheung, K.C., 2007. Optimal allocation of policy limits and deductibles. Insurance Math. Econom. 41, 382–391] are generalized here.     

On integral inequalities of the Sobolev type

Summary In this paper some new integral inequalities of the Sobolev type involving many functions of many variables are established. These in turn can be used to serve as generators of other integral inequalities.     

Multiple positive solutions for discrete nonlocal boundary value problems

In this paper, we investigate a second-order nonlinear difference equation with sign-changing nonlinearity subject to two different sets of nonlocal boundary conditions. The explicit expressions of the associated Green's functions are presented. By using a recently developed fixed point theorem, we establish sufficient conditions for the existence of multiple positive solutions of the boundary value problem.     

Experimental study of enhanced emission of the laser-ablated plume in backing gas

The effects of background gases on the optical emission of the excimer-laser-ablated plume from a brass target have been studied experimentally. It is found that the plume emission can be enhanced significantly in a proper gas ambient. In hydrogen, the highest peak intensity is detected, and in argon, there is a distinctive difference in the pressure-dependent emission between in He and in the other three gases, Ar, N₂ and H₂. Moreover, the monitored line peak intensity remains unchanged in Ar and N₂ and increases in H₂ within a distance above the target surface; but in He, the observed peak intensity decreases with distance like in vacuum. Furthermore, the emissions of several more atomic lines of Cu and Zn atoms from the plume are also found to be enhanced in the same manner in gas ambient. Some physical processes involved in the plume expansion and the possible mechanisms for the enhanced emission of the plume in backing gas are discussed.     

Analysis ofK→3Π decays in chiral perturbation theory

Using the recently proposed higher-order chiral Lagrangians determined from the integration of nontopological chiral anomalies, we calculate corrections to the current-algebra analysis ofK→3Π decay amplitudes expanded in powers of the Dalitz variables. Effects of quartic-derivative weak chiral Lagrangians are determined through the use of short-distance effective weak Hamiltonian and the factorization method. We find that (1) the constant and linear terms in the amplitude for ΔI=1/2K→3Π are in excellent agreement with experiment; the previous discrepancy of (20–35)% between current algebra and data is thus accounted for by the higher-order effective Lagrangians, (2) the penguin interaction does not play an essential role in the ΔI=1/2 rule, for otherwise it will lead to a large disagreement for the constant and linear terms, (3) one of the two quadratic terms in the ΔI=1/2 process, which arise from the quartic chiral Lagrangians, is in accord with data within experimental errors, while the other is off by four standard deviations, (4) the linear term in the ΔI=3/2 transitions is in good agreement with experiment and contributions from quadratic terms are sizable.     

Nonlinear static and dynamic analysis for laminated,annular, spherical caps of moderate thickness

Based on Timoshenko-Mindlin kinematic hypothesis, the shallow shell theory is extended to include the transverse shear deformation for the nonlinear axisymmetric dynamic analysis of the symmetric cross-ply shallow spherical shell. Using the orthogonal point collocation method and the Newmark scheme, an iterative solution is formulated. The numerical results for the nonlinear static and dynamic responses and dynamic buckling of these shallow spherical shells with circular holes under uniformly distributed static or dynamic normal impact loads are presented and compared with available data.     

Ruthenium carbene complexes containing bidentate and tridentate PO ligands

Treatment of [Ru(CHR)Cl₂(PCy₃)₂] (Cy = cyclohexyl) with Tl[N(Pr₂ⁱPO)₂] and AgL_OEt (L_OEt⁻ = [CpCo{P(O)(OEt)₂}₃]⁻) afforded the Ru carbene complexes [Ru(CHPh)(PCy₃)Cl{N(Pr₂ⁱPO)₂}] (1) and [L_OEtRu(CHR)(PCy₃)Cl] (2), respectively. Chloride abstraction of complex 2 with TlPF₆ in MeCN afforded [L_OEtRu(CHPh)(PCy₃)(MeCN)][PF₆] (3). Complexes 1 and 2 are capable of catalyzing ring-closing metathesis of diethyl 1,2-diallylmalonate. The crystal structure of complex 2 has been determined.     

Metabolic profiling of meat: assessment of pork hygiene and contamination with Salmonella typhimurium

Spoilage in meat is the result of the action of microorganisms and results in changes of meat and microbial metabolism. This process may include pathogenic food poisoning bacteria such as Salmonella typhimurium, and it is important that these are differentiated from the natural spoilage process caused by non-pathogenic microorganisms. In this study we investigated the application of metabolic profiling using gas chromatography-mass spectrometry, to assess the microbial contamination of pork. Metabolite profiles were generated from microorganisms, originating from the natural spoilage process and from the artificial contamination with S. typhimurium. In an initial experiment, we investigated changes in the metabolic profiles over a 72 hour time course at 25 °C and established time points indicative of the spoilage process. A further experiment was performed to provide in-depth analysis of the metabolites characteristic of contamination by S. typhimurium. We applied a three-way PARAllel FACtor analysis 2 (PARAFAC2) multivariate algorithm to model the metabolic profiles. In addition, two univariate statistical tests, two-sample Wilcoxon signed rank test and Friedman test, were employed to identify metabolites which showed significant difference between natural spoiled and S. typhimurium contaminated samples. Consistent results from the two independent experiments were obtained showing the discrimination of the metabolic profiles of the natural spoiled pork chops and those contaminated with S. typhimurium. The analysis identified 17 metabolites of significant interest (including various types of amino acid and fatty acid) in the discrimination of pork contaminated with the pathogenic microorganism.